The Buffer Capacity of Polyelectrolyte Microcapsules Depends on the Type of Template

Abstract

One of the key physicochemical parameters of polyelectrolyte microcapsules (PMCs) is their buffer capacity (BC). The BC of the microcapsules allows for an assessment of the change in protonation state across the entire polyelectrolyte system, which directly impacts the buffer barrier of PMCs, as well as the stability and physical properties of their shell. However, the buffer capacity of PMCs and their behavior under changes in ionic strength and temperature can differ depending on the type of core used to form the microcapsules. As part of this study, we revealed the buffer capacity (BC) of polyelectrolyte microcapsules formed on polystyrene cores (PMCPs) and studied the influence of ionic strength and environmental temperature on the BC of these capsules. We found that the buffer capacity of PMCPs differs from the BC of water at a pH above 8; the addition of sodium chloride leads to an increase in buffer capacity in alkaline conditions, and conversely, thermal treatment leads to its decrease at a pH of 9. The results obtained are different from the BC of polyelectrolyte microcapsules formed on CaCO3 cores, which suggests a difference in the physicochemical properties of these types of capsules. The buffer capacity of polyelectrolyte microcapsules depends on the type of template used.